The analysis of temperature dependences of magnetic moment of several new iron nitrosyl complexes in solid phase allowed the value of exchange interaction (J) between two iron ions to be estimated in each type complexes and a systematic decrease of J together with the increase in the ESR linewidth with a distance between iron ions to be observed. It was found that exchange interaction in the complexes involves two components, namely, direct exchange interaction and indirect one transferred through organic ligands. (C) 2009 Elsevier B.V. All rights reserved.